A Taboo Soul
by Scioneeris
Summary: AU. Demons are soulless. But Loki makes a pact with a certain red-eyed demon as he falls from the bifrost. He's tired of having to play the monster and the villain. This time, he wants to be selfish. Read warnings inside! Mild D/s themes.
1. The Pact LOKI

**Timeframe:**

AU. After The Avengers with Loki. Canon events are used.

**Summary:**

AU. Demons are soulless. But Loki makes a pact with a certain red-eyed demon as he falls from the bifrost. He's tired of having to play the monster and the villain. This time, he wants to be selfish.

**Pairings:**

Sebastian x Loki

**Disclaimer: **

I do not own any Black Butler/Kuroshitsuji anything (That belongs to Yana Toboso), or Marvel's Avengers. I just like playing with them and Sebastian in my own little world of storyville. I make no money by writing this fanfiction. All original characters are my own.

**Rating:**

M – Not suitable for children or teens below the age of 16 due to the warnings presented below the Author's Note.

**Author's Notes: **I have Loki and Sebastian on the brain. *tears at hair* I don't know why. I can't find any good SebbyxLoki fics either. I think they'd be a lovely, dark pairing and it just seems...nice. Sebastian would be a lovely dom, I think and Loki, well, I'll take him anyway he comes, I suppose. Gah. Apologies for this, really! Anyhow, Loki makes a pact after he falls from the Bifrost, because he thinks he's going insane, just a little bit, thanks to a little voice in the back of his head and it somehow leads to...this. Enjoy. My brain is now mush. :P

* * *

**WARNINGS: **Mature themes. dark fic, possibly. Contains slash(m/m), moments/mentions of femslash(f/f), and Het (m/f), Please remember that LOKI can shapeshift, so also features regular Loki and Lady!Loki. Nothing explicit as per FF guidelines. Possible gore/torture in future chapters. Angst. Fluff. D/s themes, light bondage, light BDSM play, possible bloodplay and fireplay. Mentions of Abuse. Mpreg(It's Loki, remember?). Alcohol. Corporal Punishment. OC's. OOCness. Very AU. Crossovers with other Marvel Characters may occur. Other warnings will be added as I see fit.

* * *

_No, Loki._

Oh, how it burned.

Staring up into that old, wizened face, searching for approval that was never there—that would never come—that did indeed burn. Angry, fiery flames that consumed the absolute entirety of his soul, it seemed and in that moment, there was nothing left.

Loki stared, one moment longer, one extra heartbeat, so that he might remember the expressions on their faces, the disappointment in their eyes. Just enough to turn the love in his heart, to hate.

And so he had no choice.

Loki let go.

"Loki!" Thor's scream followed him as he fell into the blissfully dark abyss.

"Thor!" Odin's roar came afterwards and Loki supposed that Thor must have lunged after him.

But there is no other sound as the dark void swallowed him whole.

Odin has caught Thor.

He has let Loki fall.

And somehow, that is the very last straw.

In everything that he has known and been, up to now, Loki has had it. He has tried so much, so many different things and it has never been enough and only now, does this truly bother him. He had once thought that it would always be a constant competition, to try and win Odin's approval, to take his one-eyed gaze away from the golden prince of Asgard, but now, such thoughts are empty, pointless dreams and they will never come to pass.

The void is cold and empty. It is everything that Loki should hate, but does not. He has always felt cold. The cold has always welcomed him. Now is no different. It is empty, but then again, Loki has always been empty. Empty and alone, this is surely no different at all.

The darkness seems to swirl, but it is hard to tell with the play of shadows and the lack of immediate light.

So Loki does not hesitate to let his mind wander. If his consciousness shall be taken from him, then he wants this to happen on his own terms. There was one final failsafe he had set into play.

One last contingency plan that he hadn't thought he'd need to use.

One choice. One chance.

* * *

It is strange to move when one is falling, but there is little time for thinking of such disconcerting things. Loki drew a knife from the curve in his leathered armor and it took a mere burst of his magic to steady himself enough to reach into his own void.

Here is where he dealt with the traitors of Asgard.

He did not sit idly upon the golden, gleaming throne.

He did not solely seek for revenge and hate.

He did his duty to his people and his king.

But no one will ever know.

They might recall a few missing faces, a few missing names, but no one will ever know. And it will be such a strange, odd mystery, that no one will ever think to investigate.

For Loki has been careful, so very careful.

And when he reached into his own, personal void of darkness, pain and despair, the scent of blood is nowhere near as nauseating as it could be. Instead, he can feel the bodies, some fresh, some decayed, the stench filling the void around him.

And there is blood.

Loki whispered the words to summon the dark creature. This was his last resort. He intended to unleash it on Asgard, or better yet, Thor.

But that opportunity is long gone.

It will never come again and all his preparation will be for naught, except—except there is one thing in the back of his mind that has never silenced. No matter what he has done and how he has done it, there is one malicious whisper in the darkest, shadowed corner of his mind, reminding this fallen, dark prince of all that he will never be and the wretched secrets that he craves.

The dark, beautiful things he desires that he will never have.

Never.

But the ritual is simple, the words have already been spoken.

And then he feels it.

The darkness shifting and warping around him.

The summoning is complete.

The demon wakes.

It comes.

Loki cannot contain the shiver of anticipation that rolled through him. The little voice in the back of his head, has quieted. It does not know what to make of this final plan of his. Loki smirked. He is glad. He wanted a clear head for this.

"…who dares summon me…?" The voice is old, ancient and so, very, very deliciously dark.

Loki sucked in a single, suffocating breath. "I do. I am Loki of Asgard." But even as he said the words, Loki corrected himself. He is no longer of Asgard. He is of nowhere. He is now no one and nothing, of nowhere. "Formerly." He added.

There was a mocking laugh. "Then, formerly Loki of Asgard, you know you have summoned me?"

"I do." The answer is quick, clear and straightforward.

"Then will you make a pact?"

There is the faintest hint of redness in the blackness and Loki can almost see the shadowed, twisted shape that is this hideous thing he has dared to summon.

"I will."

"…so sure, you are?..." The voice laughed again. "Very well then, I shall grant whatever you desire, in exchange for your soul."

"It is my soul I wish to bargain with." Loki heard himself say.

"There is no bargaining for your soul. If you agree, then there is no heaven, there is no hell. I shall devour you whole. Until such a time, I shall serve you for the duration and entirety of your request."

"I wish for a soulmate." Loki laughed. The sound was hollow, frightening and mad. "I wish for a soulmate to stand beside me until I have fulfilled my destiny. Be it the bringing about of Ragnarok or the destruction of the Nines one at a time or simply the descent into madness, I desire one such soulmate. One that would stand beside me through it all. One that I may destroy and one that would destroy me too. One I can hurt, one that can hurt me back. One I might eventually grow fond of, even as it kills me."

"…and that is your wish?..."

"That is my wish." Loki coughed. The action reminded him that he was, essentially, in freefall and that hurt, somehow. "It is a selfish, foolish, pathetic request—but that is all I wish." He half-smirked. "In turn, this wretched, blackened soul is yours."

"Black, you say? But yet it struggles onward, fleeting and fluttering, trying to reach something better, brighter…how generous…it may take time to find this soulmate of yours."

"I do not want someone." Loki is proud to note that his voice is steady. "I want you."

There was a whispered hiss. Then nothing. And then—"…a demon has no soul…"

"Do not _lie_ to me!" Loki snarled. "I am the god of lies! I am no mere _mortal_!"

"Then you know that such a soul can never be yours."

"I know it is taboo." Loki returned, evenly. "I also know it is not impossible. This is my request and if you cannot grant it, then be gone. I have more important things to attend to."

"…what you desire will take time to bring about. I shall require a taste of your soul to plead your case."

"My soul is all that I have to offer. I cannot give away a simple taste without some sort of guarantee." Loki snapped back.

There was a concentrated hum and then the shadows twisted even more and suddenly, the fall stopped. The blackness faded to a black-veined redness that surrounded them both. The shadowed, feathered figure and his falling figure.

Loki found himself sprawled on the ground, with pointed-heel boots a mere inch away from his royal face. He did not flinch, recoil nor acknowledge them. He merely lay there.

"I keep my word." The voice is soft, whispery and so very, very dangerous. "and I will destroy you and hurt you. You know this…but if that is what you wish, then as proof, I will mark you now…where would you like it?"

"I care not."

"…very well then…" The gloved, slender fingered hand, stretched toward the fallen prince.

Loki let himself be pushed over. He gasped when the hand ripped down the front of his tunic, parting his armor with a thread of dark magic. The glove melted away from the hand, that rested right above the prince's heart.

Smooth, cold and powerful, the hand pressed down.

Loki screamed.

The demon laughed. "What a delicious soul you have, my little Raven." It purred. "Keep out of trouble, until I return. _Behave._ If you can."

And the ground fell out from beneath them.

This time, Loki fell to the sound of the eerie laughter, ringing through every fiber of his being, punctuated by the burning, aching pulse that throbbed over his chest. He vaguely realized that his clothes and armor had been fixed and replaced.

But the darkness swallowed him again and this time, Loki let it.

* * *

With the final smash from the Hulk, Loki choked on the gasp that lurched from his lips. He couldn't draw a single, necessary breath. Black spots swam before his vision and he knew he could not hold on much longer.

The brand on his chest ached, throbbing in that way that reminded him of all that he had given up and yet, how nothing remained.

A sudden jolt of fire made him lurch upwards, gasping as the painful fire coursed through his body, granting him a mild reprieve by the way of a single, full breath. A whisper of darkness settled beside him and Loki suddenly _knew._

He froze.

Even as he felt the presence of those pesky Avengers approach.

And then, he saw them.

Shiny black boots, polished to perfection. Pressed black slacks, impeccably tailored and exquisitely crafted. A matching vest, a matching waistcoat, a crisp white shirt, with spotless white gloves. Ebony tresses and blood-red eyes to accent the pale, grey-white skin.

_Demon._

And Loki suddenly knew.

And he knew that Thor would know as well. He saw the moment when Thor knew what the creature was, those baby-blue eyes grew wide and he threw a strangled warning to his comrades.

But the warning came too late.

The lovely man-creature _moved._

And Loki stared.

Beauty, death and grace, all in the same breath. In a quick blur, the Avengers are driven back and Loki is plucked up from the hole in the ground. He can barely guide his trembling fingers to lock around the slender neck, even as the brand pulses again, angry—red-white-hot.

And then, they vanished.

* * *

Loki felt the rush of wind and closed his eyes to the expected sensations and images. He waited until he felt some semblance of a closed room settle around them and then, he was gently set on something soft.

Emerald eyes opened in confusion, wonder and despair.

The red eyes of the creature met his gaze steadily and then, with deliberate movement, the white gloved hands reached forward and began to undo the fastenings that kept Loki's armor together. "Trying to take over earth, making a pact with a miserable scrap of existence on pain of death and baiting your pesky brother's secret little posse." There was a little, soft sigh. "That, my little Raven, is _not_ behaving."

Loki stared.

He couldn't think. He couldn't process. He couldn't even try to make sense of it.

He didn't want to.

But then, cool, smooth lips pressed against his.

And the barest hint of affection was all that ugly little voice inside of his head needed. Loki closed his eyes in shame as he felt the little dark thing squirming and writhing, working itself out of the little corner where he'd shoved it.

It took a scant second before Loki kissed back.

Those cool, smooth lips kept him occupied as those gloved hands undressed him with a deft, expert manner.

Loki hissed softly in pain, against the next kiss when cool air hit his exposed chest, the bruises from the Hulk's treatment, showing plainly against his pale skin.

_It hurts._

But Loki ground his teeth together, to keep the sounds inside. He forced his breath in quick, short patterns and focused his magic. He would have to heal and—ow!

A choked gasp escaped this time and Loki stared up at the shirtless, lithe figure crouched over him. Perfect, pale skin, chiseled muscle and lethal potential all wrought into one being. "Does it hurt?" The creature whispered. "Let me hear you…"

_Yes! It hurts…by the Norns, of course it hurts!_

But Loki stubbornly kept his lips pressed together. He tried not to flinch when those cold hands danced along his sides.

And then, suddenly, his clothes and armor have vanished and there is nothing between them, save the silken fabric of this creature's tailored trousers.

"Consider this your punishment." The red-eyed demon purred. "I warned you to behave…and it will take some effort to fix the mess you've made. I did not wish to spend tomorrow righting the riots you have caused."

"god of mischief." Loki managed to gasp out, as one hand pressed a particularly painful—and sensitive spot—before his magic managed to heal that hurt. "Expect—it." He forced the words out, channeling his magic to continue with its healing. It swam beneath his skin, barely there, worn and exhausted. He needed to rest. It needed to rest.

But now, his weary body was slowly coming to life, burning and twitching with need as his new…soulmate, took care of him.

"Hmm. Yes. As if Chaos simply follows you?"

Emerald eyes met red.

Fire and ice burned.

Loki felt his magic flare.

He felt the demon's one do the same.

So this would seal their deal.

He did not look away, as the magic twined and coiled between them. He did not shiver as the chains wrapped around his soul and a sliver of light flickered into existence in his own, dark world. He did not regret for a moment, when that lovely man-creature finally descended upon him with deliberate, erotic thoroughness.

…_yes. Finally…_

The little voice in his head cheered.

Loki ignored it and simply lost himself to the pleasure.

* * *

**A/N: And there we go. Yes. That was Sebastian. **


	2. Sealing The Deal SEBASTIAN

**Oh wow. I'm really happy there are folks who like this pairing. Sebastian and Loki FTW! It's kind of stuck in my head and I hope I am doing them justice. This chapter is from Sebastian's POV, sorry for the wait!**

* * *

Desperation is the name of the being beneath him, Sebastian mused. He cannot keep from licking his lips at the delectable sight of the wounded warrior prince stretched out on the silken sheets of their bed.

_Their _bed.

It has such a lovely ring to it.

He will take his time with this one.

When Loki had first summoned him out of his restless boredom and into that tasteless void, he had not expected anything near this—exquisite. And Loki is certainly exquisite. He has a loud mouth and busy hands, but his body betrays him in moments like this, as Sebastian watches.

Yes, it really has been far too long since he has been able to have some decent fun.

Loki is a natural submissive, a powerful entity desiring to give himself to the care of someone who would not abuse him, in order to better control and craft the magic that lives in him. He craves a gentle touch and a harsh master. A study in contradictions, as his demands in settling their contract has led the demon to believe.

Someone has been cruel to his Raven.

Sebastian knows this. He can tell. In the false bravado, the muted whimpers of pain and the crumbling masks that Loki struggles to continually rebuild. His lovely new pet is falling apart at the seams and it appears that no one has noticed.

No one cares.

Pain is a friend of pleasure, Sebastian knows. He will show this to Loki, perhaps now, perhaps later, perhaps for the entirety of their time together. He was completely unprepared for the tantalizing scent of the godling's soul.

That had been the actual push to send him to seek permission to bond with the green-eyed beauty. It was no loss or inconvenience to him, to spend a few centuries, even, with such a lovely creature and receive a delightfully tasty reward at the end.

Sebastian smirks.

It is hard to keep from doing so. But he will think of things later, for now, he wants to enjoy this moment. A moment he almost didn't have when he returned to the earthen realm and discovered his new plaything hammered into the floor of a mortal structure.

His anger nearly simmered over, but centuries of practice lie within his existence and Sebastian knows to control himself, even when he is out of control. So he attacks, as it seems to be the best course of action and disappears with his little Raven.

When they materialize in the apartment, he sets the trembling figure on the edge of the newly made, pristine bed. He grimaces at the thought that blood will stain the white sheets. And then, he is reminded that he does not care of such things.

Loki stares at him with wide, expressive green eyes that say more, perhaps, than his bruised mouth can.

Sebastian does not answer those unspoken questions as he busies himself with calming his raging temper, by painstakingly removing the complicated armor that hides his prize. There is a jolt of surprise in Loki's gaze, as if he cannot understand how Sebastian has figured the correct way to manipulate and remove the leather and metal.

But centuries of experience bring memories to the surface and Sebastian simply _knows._

Soon, the demon hears himself speak, a voice smooth as velvet, betraying the fact that his temper has not yet settled. He did warn Loki, he had. He'd specifically mentioned 'staying out of trouble' exactly how difficult a request had it been?

"Trying to take over earth, making a pact with a miserable scrap of existence on pain of death and baiting your pesky brother's secret little posse."

Sebastian cannot help giving a sigh at the sight of those green eyes growing impossibly wider. He is silently grateful that it appears they will be a good fit, for he cannot let this little thing go unpunished and while he has no desire to break his new plaything before they have even started, there is something in Loki's manner that answers the unspoken question between them. Loki will not fight him. "That, my little Raven, is _not_ behaving."

The godling shudders, faintly—so very faintly—and Sebastian smirks, again, as he leans forward. It doesn't take much to close the distance between them. There is nothing between them, after all. He touches his lips to Loki's in a testing, careful manner.

He needn't have worried. There was no hesitation before Loki returned the gesture of affection, the kiss slightly desperate, and definitely needy.

Sebastian smiled into the kiss and shifted forward, adding a little more closeness, a little more pressure, to ease the tension in that deceptively strong body. The tremors were from stress, fatigue and perhaps injury.

Sebastian can smell the blood, pain and yes—fear. But he does not need Loki to fear him. There will be more than enough time for that later. He deepens the kiss again, teasing and light in the manner, as he continues to undress the trembling form.

The next sound from Loki is a hiss of pain, when the cool air finds every colorful bruise blossoming across his pale skin. Sebastian can sympathize. Injuries that will not kill, but will burn, ache and hurt as a constant reminder that you were just not good enough.

A reminder that Loki does not need right now.

For a moment, Sebastian almost wishes he knew what exactly caused such injuries. But it will be no hassle to find out on his own—later. For now, he wants Loki focused on him. There is still one thing they need to do before this bond in finalized.

With a whisper of his own darkened energies, Sebastian casts aside his impeccable suit of black, removing his gloves in the usual way. His bare hands skim over the bruised, sore skin and Sebastian notes the way that Loki grinds his teeth together.

His Raven is wounded, but trying to be strong.

Sebastian presses a little harder on a patch of red and purple mottled skin. He is rewarded when a choked gasp escapes and those green eyes darken to a near black. Ah. That is a lovely look. The despair has been replaced by something more likeable—something decidedly darker.

When the demon settles over him, Loki only continues to stare. "Does it hurt?" Sebastian whispers. His nimble fingers skittered over that hairless chest, marveling at the smooth skin, even when bruised. A few scrapes were healed beneath his questing fingers and he could sense the cracked ribs and bruised inner workings. He trailed one sharp fingernail down a raised stripe of pink bruise. He pressed a little harder, coaxing the darker energy to meld with the lighter, green twists of magic.

Loki pressed his lips together.

"Let me hear you…"

But Loki holds his silence even when Sebastian continues to touch him, even when his clothes and armor are banished elsewhere. Loki remains still and silent as Sebastian runs his hands up and down the slender planes of his torso. Sebastian finds that he enjoys the feel of it.

Loki flinches when those pale hands begin to tease him. It starts almost innocently, with light touches, ghosting over his chest and then firmer, even rubs, circling around one dusky nipple and then the other.

Sebastian wonders if his hands are cold. Temperature is different to him than it is to others and he wonders, as goosebumps prickle to life across Loki's exposed skin. Not that it would stop him, but Sebastian finds it odd and interesting. He lowers himself a little closer, watching the reaction from the trapped godling. Loki breaths are short and shallow and his paleness has taken on a few pinkish hues.

Sebastian smiles. He has retained his silken trousers for the moment, but he will lose them after he has made Loki lose his mind. And then, of course he smirks. "Consider this your punishment." He purrs, softly. Enjoying the way that Loki's breath hitches in his throat, and those slender fingers clench in the soft, cotton sheets.

A series of nips and kisses along that bared throat and shoulders, adds a hint of emphasis. "I warned you to behave…" Sebastian's hand flashes out, catching Loki's wrist before the godling can actually touch him. He settles himself easily over Loki's thighs and captures the other hands. He pins both wrists above Loki's head and holds them there with one hand, while he trails his free hand lower to something more—interesting.

"It will take some effort to fix the mess you've made. I did not wish to spend tomorrow righting the riots you have caused." Sebastian notes that his energies are coaxing Loki's magic to heal him at a faster rate than before. That is an interesting development. He trails one hand down from the hollow of Loki's neck, down his torso, over the dip of his navel and then, finally, to the dark patch of curls where his prize has begun to stir.

"god of mischief." Loki managed to gasp out, as the hand holding his wrists tightened when he tugged at the restraint. He was in no condition to extract himself. "Expect—it." The magic drew heavily on his body, leaving him bare to the basest instincts of a creature responding to its lover.

The former coolness was replaced with a slowly warming, torturing fire.

Loki bit at his lips as Sebastian leisurely stroked him, teasing, with light touches and whisper-soft caresses, before suddenly fisting him. A choked cry causes him to bite through his lip. Speckles of blood decorate his pale face.

Sebastian leans forward, his thumb circling the head of Loki's cock. Red eyes watch carefully as Sebastian kisses chastely, then carefully as he laps gently at the wound and then roughly thrusts his tongue into the warm, willing mouth.

Loki trembles beneath him, unable to move away, but not quite wanting to. He keens softly at the stimulation, alternates from slow and firm, to quick and rough. The last tendrils of his magic arch up and are met with equal show by Sebastian's own darkened energies.

"As if Chaos simply follows you?" Sebastian murmurs. He gave a single, sharp tug and angled his head to bite one bejeweled ear.

Loki twisted and shuddered, pleasurably as his release spilled over. Heat flushed his skin and pinked his cheeks, embarrassed that he hadn't been able to hold out very long. He had better stamina that than! He tried to hide his face, only to find that he couldn't turn away from the insistent, dominating kisses.

Sebastian chuckled darkly. "You cannot hide from me." He licked a trail from ear to nipple, then blew softly on the wetness. Loki squirmed. "I will always know where to find you." Sebastian pressed his lips to the seal emblazoned on Loki's chest, directly over his heart. It looked quite lovely. "Always."

Emerald eyes met red.

Fire and ice burned.

Sebastian pushed his magic through the seal, burning through the final defenses in Loki's personal walls. The green and red twined together, settling into a gorgeous, powerful mix, as the bond was birthed, forged stronger and then hidden away.

Loki screamed, the sounds swallowed by Sebastian's kiss, before his wrists were finally released. Loki tugged at them, faintly, the best he could manage—still. But they did not move.

A wicked smirk settled on Sebastian's marble features. "Not just yet, my little Raven." He said, amused. "Surely you did not think I would enter into such a contract without knowing all of the consequences?" He presented two fingers to Loki's bloodied lips. "Suck."

This would seal their deal.

* * *

**A/N: And there we go! Chapter 2. Gah. I don't think I did Sebby justice. But I didn't want to make him too dark and demanding just yet...and I like it when Loki squirms. :P Thanks for reading! Yes, I will be cross-posting this on AO3, the explicit scenes/missing lemons will appear over there and I'll let you know when a different scene is posted there. **

**Review replies are in the forum! : fanfiction(heresadot)net/forum/Reviews-and-Randomness/113711/**

**~Scion  
**


	3. Sealed LOKI

**A/N: This chapter turns out to be mildly explicit, so the full version is available over at AO3 = Archive of our Own, at the link below. Replace an actual dot and enjoy. ;). You can find the link to my AO3 profile on my profile page here. Scroll down until you see the links, or look me up under "Scioneeris". **

archiveofourown(HeresaDOT)org/works/491193/chapters/974933

* * *

Embarrassment. Humiliation. Pain. Pleasure.

It all burned together and somehow, he didn't mind, didn't care and didn't want to care. Loki had balked at first, understanding the unspoken when Sebastian had pressed those two fingers to his lips. It would seal their deal, yes. It would also cement their roles for the entirety of this deal.

He struggled in vain.

He did _not_ want to be the bottom in this relationship.

Never.

Definitely never.

He was not submissive, he was _not_ weak and he was not some wench to be mounted and-! The words trailed off as Sebastian's other hand scratched thin lines of pleasurable fire from his navel to his groin. Just enough pressure to keep from being ticklish and just light enough to pull sensations from him that he hadn't known existed.

He did not want this.

But yet, here he lay, restrained by a being that screamed of dominance and elegance, coaxed to acknowledge that all he could want was his—if only he could willingly submit.

If.

The last shattered, darkened sliver of pride curled up and died.

Loki squeezed his eyes shut.

The fingers tapped on his sore lips and then feather soft kisses danced over his eyelids. "Shhh. Don't hide from me, Loki." The name somehow sounds sinful falling from those lips. "Let me see your eyes. Show me what you're thinking."

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**Thanks for reading!~Scion**_  
_


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